Shanadfeldman...
Bipolar do not get better. This is their life.
When there is a true (and long term commitment) to taking meds and staying in control, then it is possible for the bipolar relationship to hang together. BUT..remember... it is only as long as the bipolar stays commited to staying on the meds.
What usually happens (check it out... the percentage is quite high), the bipolar hates the lack of the 'highs' and refuses meds (my ex boyfriend)...or they think they are "all better" and quit taking meds. Sometimes it isn't until the major explosion happens again that the partner knows!
The abuse is both emotional and psychological. Part of it is done to control you.
I am sorry for your trouble. I understand your situation VERY VERY well. Please. Use the Ann Landers question: are you happier with him or without him?
Would you be in need of therapy yourself if is wasn't for him?
I know how hard this all it. Bless you and take care of yourself.